Watching Twyla Tharp’s latest dances unfold, at Lincoln Center’s David H. Koch Theater on November 18, it was easy to believe the Dance Boom of the 1960s never ended. Not one to be shy, Tharp unveiled her new works with a flourish of trumpets presenting two masterpieces in contrasting styles on a program celebrating her 50th anniversary as a choreographer. While marking a personal milestone for her, this colorful burst of inspiration should also give us notice that the paint is still wet on America’s dance scene.

Tharp’s new Preludes and Fugues offers a formal suite of dances, exquisitely calibrated and set to excerpts from Bach’s "Well-Tempered Clavier.” In the second piece on the program, titled Yowzie, disorderly impulses rule and a gang of scruffy but loveable characters go on the prowl, while we listen to music by Ferdinand “Jelly Roll” Morton and other NOLA greats, selected from an album called “Viper’s Drag.” Santo Loquasto has supplied the costumes and the look of each piece, giving Preludes and Fugues a low-key elegance and making Yowzie psychedelic, with the dancers wearing tie-dye rags and with planets spinning on the backdrop.

A fanfare introduces each dance; and the fanfares, danced to music by John Zorn, are finely detailed miniatures. Tharp’s imagination has never been more active — particularly in Preludes and Fugues, where she draws from an archive of movement material she has been building over the years. In Preludes and Fugues, self-contained but complementary scenes follow one another in beguiling and apparently effortless succession.

In reality, Tharp’s process is anything but effortless. She admits to terrible doubts. Her new pieces look terrific in an off-handed way, however, because despite or perhaps as a result of personal anguish she has achieved mastery. While continuously adding to her stock of movement ideas, she has also spent five decades experimenting and honing her craft. Over the years she has assembled vast contrapuntal engines and has staged intimate moments for lovers. She has programmed austere exercises performed in silence; and promoted disheveled, mass happenings. She improvised dizzy, loose-limbed riffs; set athletic challenges for dancers in tank tops and sneakers; and designed taut, classical variations for ballerinas on pointe. She went commercial with hard-selling Broadway numbers; and filmed close-ups in Hollywood. She gave us dances in which she plumbed the near, the far; the up, the down; the fat, the skinny.

"The Second Fanfare"; Photo by Sharen Bradford

What’s astonishing is how much of this experience Tharp has managed to slip into Preludes and Fugues, without distorting its formal outlines. Inspired by Bach’s stylistic range in “The Well-Tempered Clavier,” and responding to the terrorist attacks on 9/11, Tharp has used the score’s diversity as an excuse to pack her opening dance with a range of subtly affecting situations.

The cast enters flying in the "First Fanfare", their bodies arched or jack-knifing, sliding and covering the space in great bounds. They arrive by twos and, once all are assembled, symmetrical patterns emerge reassuring in their orderliness. This introduction plants a structural idea, as the pairs of dancers anticipate Bach’s matched sets of preludes and fugues. Yet Tharp concludes with something less cerebral — a provocative, come-hither glance, as two women look over their shoulders inviting us to follow them into the main event. The “First Fanfare” has swept past leaving us breathless.

The next thing we see is a couple embracing. John Selya and Savannah Lowery swivel cozily, try out a polka step and finally reveal their hearts’ ambition in a reach-for-the-stars ballet lift. With Lowery’s lines unfurled dramatically above Selya’s head, they circle toward the exit — Tharp’s first reference to the so-called “circle of fifths” that Bach follows in his exercises for piano. Her Preludes and Fugues will end with circles, too. Returning to the C Major Prelude that begins the series, she will arrange the cast in a ring, facing inward with hands clasped, as if the love uniting the opening couple had spread through the community.

Along the way cross patterns will bear Christian witness. Matthew Dibble and Amy Ruggiero are the spunky central couple, making courtly bows that recall the Baroque danse à deux but also bouncing cheerfully and leveraging their weight in complicated lifts. The ensemble surrounds them like a cloud, each member spinning woozily, and they make a gate for the couple to pass through. With Dibble and Ruggiero downstage center, the dancers behind them travel back and forth tracing a giant cross on the floor. Then Dibble and Ruggiero intersect, she slung tightly between his legs, and the two of them form a second cross with their bodies. Compositionally this may be Preludes and Fugues’ most dazzling episode, although Tharp is as much at home creating stage pictures that appear random.

When Tharp varies the scene in ways we can observe easily, the choreographer shows off her craft. Three men dance independently in one section, and next three women dance in unison. Those dancers aren’t just moveable game pieces, however. The men act boastful and competitive, rough-housing while the women will cooperate as a team. Preludes and Fugues would be less remarkable if Tharp merely checked off a list of design options. Instead she gives the dancers human traits and personalities; and here’s where things get really interesting.

Preludes and Fugues; Photo by Sharen Bradford

On a program where Preludes and Fugues is supposed to be the sober and responsible one, remaining dignified and above all that while its depraved twin, Yowzie, indulges in every folly and vice, you don’t expect to find Ramona Kelley bouncing like a ball and (with an assist from Reed Tankersley) ratcheting downward until she’s nearly flat on the ground. Yet Preludes and Fugues makes room for visual gags like this one in the double duet, where, in the background, Nicholas Coppula and Eva Trapp latch onto each other and he hoists and drags her, the two of them as gung-ho and as awkward as teenagers on their first date.

Tragedy lives here, too, alongside flirtation, abandonment and despair. In a key scene, Ron Todorowski has an emotional meltdown, suffering spasms while the two tall women in the company — Lowery and Kaitlyn Gilliland — brush past him unseeing and we can feel the chill implacability of death. The antidote to the horror Todorowski contemplates, and which the choreographer faced herself on 9/11, is life itself replete with the joys and trials of coexistence. Preludes and Fugues is rich in emotional nuances, with Tharp adding contrasts and transparent shadows so we can see relationships more clearly. This dance contains worlds.

The “Second Fanfare” plunges us into theatrical fantasy, with dark shadows etched against a satiny red backdrop and the dancers’ silhouettes rendered exotic by costumes with fussy details and extravagant, couture hats. The graphic, two-dimensional quality of this introduction reflects the fact that what follows will be an adult cartoon.

Yowzie cheerfully embraces vulgarity, yet this slumming-after-hours piece is arguably more sophisticated than the up-scale Preludes and Fugues, because Tharp’s free-form approach to the second half of her 50th-anniversary program demands the utmost confidence and skill. No one takes risks like this, unless she knows exactly what she’s doing. The dance focuses on a single couple — Dibble and Rika Okamoto — whose drunken benders; marital jiu-jitsu; same-sex experiments (he); martyred self-aggrandizement (she); and druggy, all-is-forgiven reconciliation at the end give the piece a loopy narrative arc. They meet other characters along the way, notably a pair of effeminate men (Selya and Todorowski) who lead Dibble down the garden path; and Tankersley, a young man infatuated with the long-legged beauties we saw in a very different context in Preludes and Fugues. Here Lowery and Gilliland are curvaceous glamor girls, not basilisks, and with the insatiable appetite of youth Tankersley can’t get enough of them. So, in the end, he gets none. The characters and their foibles provide the structure, but Yowzie has a moral framework, too; and Tharp suggests these frazzled party-goers get what they deserve.

During the course of this evening, all the dancers have their moments to shine and they do — especially the unsinkable Dibble, sparkling Ruggiero, sly-boots Selya and Todorowski, who comes alive whenever he has the spotlight. In Yowzie, however, Tharp goes out of her way to create a starring role for Okamoto.

Yowzie; Photo by Sharen Bradford

Her ebullient partner, Dibble, has adventures, but Okamoto’s character goes on a journey that involves pain and loss. When she sees her former squeeze in the arms of his new pals, the shock bats her into another dimension. Slack-jawed with amazement, she performs a double-take in slow motion as if reviewing every moment of their history together and identifying, in retrospect, all the signs that he was queer. Then she falls into a drawn-out and melodramatic tailspin. Dibble’s defection upends her, and he finds her later slumped helplessly with her butt in the air. A squad of dancers stampedes over Okamoto’s prone body; and then the victim undergoes a bizarre metamorphosis: swelling, hulking and dragging her knuckles as if she had devolved into an ape. Tharp knows this lumbering caricature wouldn’t be as funny if Okamoto weren’t a dancer of such fine-boned delicacy; and presumably Okamoto knows this, too. She gives a shrewd and hilarious performance heading into another scene with a Holy Week procession in which a shuffling and praying crowd exalts Okamoto, carrying the now canonized victim on high. The second half of this show belongs to her.

Badda-Boom, Badda-Bang

Nothing is ever what it was, but watching Tharp disport herself here, waving at us from a 50th-anniversary platform heaped with bouquets, who could say the golden age of American dance is over? Tharp reckons her beginnings from a 4-minute piece she presented at Hunter College in 1965. Did that performance take place at the height of the Dance Boom? How could it have been the height of anything, if Twyla Tharp’s phenomenal career was just getting started? And the feisty 74-year-old dance maker has given every indication she’s not done yet. Done, as in finished, kaput? Are you kidding? A retrospective program would have sent a valedictory message, as Tharp well knew. Creativity points to the future. Tharp isn’t even tired.

It would be easy to confuse the commercial debasement of America’s mass media and the shriveling of print journalism with a decline in American culture generally, but, for dance at least, the present moment feels rife with talent and possibilities. Those who don’t see it may simply be unwilling to acknowledge generational change. Tharp’s anniversary blow-out suggests that we’ve been looking at our history all wrong, and we need to alter our mindsets. Maybe the so-called Dance Boom of the 1960s was more of a bang — a Big Bang that created the universe we live in today. In this dance universe, three or more generations of choreographers work simultaneously while Tharp and a scant handful of her contemporaries morph from rebellious upstarts into the revered elders we thought we had lost. Making up our minds that the Dance Boom was really a Dance Bang means we still need to worry about entropy, but we should not give in to despair because one or two stars have winked out (like Balanchine, for instance). Our universe is bigger than that now, and the dance scene is more mature.

The major problem afflicting dance in our day, which Tharp’s anniversary celebration also points to and underscores, is the dance community’s failure to make provision for the future and adopt the structural changes required to preserve its achievements — a circumstance that greatly aggravates the impact of generational change. Though Preludes and Fugues, Yowzie and the Fanfares were created for a particular purpose, they are much more than “pièces d’occasion” to be savored and then discarded. One could watch these wonderful dances dozens of times, either together or separately, and still not exhaust their beauty. Yet here we are, a month after their local premiere, and they’re already gone. With Tharp, we don’t need to wait for spots of decay and other ominous signs of “death of the founder” syndrome to appear. Because she has no company acting as a repository for her choreography, it evaporates instantly. One of the things Tharp has said about Preludes and Fugues, however, is that this work, created in the aftermath of trauma, represents “faith in continuity,” meaning the ongoing relevance of Bach’s music, and the ability of artists and human beings to persevere in the face of tragedy. But where’s the continuity for Preludes and Fugues itself?

Maybe American Ballet Theatre will adopt it, or Paul Taylor’s American Modern Dance, along with Tharp’s other orphaned repertoire. ABT owes her a season devoted entirely to her works, like the Balanchine Celebration that New York City Ballet mounted for its co-founder. No one-time celebration, no matter how extravagant, will solve the long-term problem of conservation, however. For that we need to change the way we think about dance.